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Saturday, 3 September 2016

Chapter-1 ADO.Net Entity Framework

ADO.NET is a model used by .NET
applications to communicate with a database for retrieving, accessing, and
updating data. This module will provide the necessary skills to the students to
work as a database application developer in the industry.

.NET Framework enables you to create
data centric application that enable you to access data fromvarious data sources in heterogeneous environment
using ADO.NET.

Brief History

1.Tebisco is a leading producer and distributor of
snacks in the U.S., as well as in most of the company’s 23 international
markets. In 1998, consumers spent $9.2 billion on Tebisco’s snacks,$1.4 billion more than in the previous year.

2.Tebisco started as a small bakery in Round Rock,
Texas in 1978. In a short time, its gingersnaps, macaroons, shortbread and
other cookies were popular all over the U.S. Three years ago, the management
embarked on a rapid expansion plan. They set up offices in Asia and Europe, in
addition to strengthening their U.S. operations.

3.Tebisco has got a centralized database
management system whereby the information about all the HR activities is
maintained.

3.ADO.NET
use XML to transfer the data across the application and data sources

4.User
need not remember the database commands for retrieving or updating data in the
database.

5.Microsoft
has created a family of data access technologies to help programmers build
efficient applications to access data, regardless of its source.

6.The
guidelines that can be followed for selecting an appropriate data access
technology are:

a) Use ADO.NET for writing a managed code targeting the .NET
Framework in Visual Basic, C#, and C++.

b)Use
(OLE) DB for writing a Microsoft based application, a VB 6 COM application, or
a C++ application using COM.

c)Use JDBC for writing a Java code targeting SQL Server.

d)Use
Microsoft ODBC for writing a native code targeting Windows by using C or C++.

7.One of advantage of ADO.NET is it supports
disconnected architecture .Using disconnected architecture ,application connect
to database server only to retrieve or update the data Hence it reduces the no
of open connections.

8.ADO.NET dataset is a cache of records that you retrieve
from data source. Dataset contains from one or more tables. Dataset can also manipulate
the data from application without database or by using XML.

9..NET data provider enables you to connect to
data source and execute commands to retrieve results and manipulate data.

ADO.NET is a part of the .NET Framework
architecture.

The ADO.NET
Object Model

1.ADO.NET
is based on an object model that is based on the standards laid down by W3C.

2.The
following figure shows the ADO.NET object model.

1.The
two key components of ADO.NET Object model are:

.NET Data provider

1).NET Data provider enables an application to
connect to a data source, execute commands , retrieve results, Storing the data
in a dataset, Reading the retrieved data and Updating the database.

2).NET Data provider consist of four key
components:

i)Connection:
Objects enable you to establish and manageconnection to a database.

ii)Command
: Objects enable you to execute SQL command and retrieve the results from
database.

iii)DataReader
: Objects enable you to read data in sequential manner

iv)DataAdapter
: Objects enable a database and a dataset to communicate with each other.

a)Is
a disconnected, cached set of records that are retrieved from a database.

b)Is
present in the Dataset class in the System.Data namespace.

c)Has
the following key components:

i)DataTableCollection

ii)DataRelationCollection

iii)DataTable

iv)DataRowCollection

v)DataColoumnCollection

Features of ADO.NET

1)The
key features of ADO.NET are:

a)Disconnected
data architecture

2)Applications
connect to the database only while retrieving and updating data.

3)Connection
with the database is closed, once the data is retrieved.

4)Connection
isre-established when the data needs to be
updated.

a)Data
cached in datasets

5)The
data is retrieved and stored in datasets.

6)You
can work with the records stored in a dataset as you work with real data.

7)The
dataset is independent of data source and you remain disconnected from the data
source.

Benefits of ADO.NET

ADO.NET has many
benefites:

Interoperability :

ADO.NET use XML to
exchange data, any component that understand XML can receive data from ADO.NET
.

Maintainability :

Application
created using ADO.NET are easier to manage and scale than application created
in ADO.ADO.NET enables
you to easily increase tiers in a deployed application because ADO.NET use XML
to transfer data between tires .

Programmability:

ADO.NET
simplifiers programming for various tasks such as execution SQL commands. This
enable you to increase productivity and minimize the number of errors

Performance:

ADO disconnected record
set use COM marshaling to transfer data between application . This requires
data type conversion in order for COM to recognize data types and conversion diminished
the performance of an application. ADO.NET use XML to transfer the data then no
conversion required.

Scalability

1.Database
operations are performed on the dataset instead of on the database.

2.As
a result, resources are saved and the database can meet the increasing demands
of users more efficiently.

3.With
the increase in data and the changes in business model of organization the
demand for data has increased rapidly.

4.It
enables you to reduce the open connections to the database and results in optimum
usage of resources.

Data transfer in XML format

1.XML is the fundamental format for data transfer
in ADO.NET.

2.Because a dataset is stored in the XML format,
you can transmit it between different types of applications.

a)ADO.NET is a data access programming model for
accessing the data stored in a database from a .NET application.

b)The ADO.NET object model consists of two main
components, data provider and dataset.

c)A data provider is used for connecting to a
database, retrieving data, storing the data in a
dataset, reading the retrieved
data, and updating the database.

d)The various types of data providers are:

i).NET Framework data provider for SQL Server

ii).NET Framework data provider for OLEDB

iii).NET
Framework data provider for ODBC

iv).NET
Framework data provider for Oracle

e)The four key components of a data provider are:

i)Connection

ii)Commnd

iii)DataReader

iv)DataAdapter

f)The dataset is memory-based relational
representation of data.

g)The main features of ADO.NET are:

i)Disconnected data architecture

ii)Data cached in datasets

iii)Scalability

iv)Data
transfer in XML format

I hope that the functionality of the above attribute is clear to you now.
Now you can use this code in your application. If you have further question,
just drop a line below and I will try to answer you as soon as possible.

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